<HTML>
<BODY BGCOLOR="white">
<PRE>
<FONT color="green">001</FONT>    package gates;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import mathtools.Complex;<a name="line.3"></a>
<FONT color="green">004</FONT>    import mathtools.Matrix;<a name="line.4"></a>
<FONT color="green">005</FONT>    import register.Register;<a name="line.5"></a>
<FONT color="green">006</FONT>    <a name="line.6"></a>
<FONT color="green">007</FONT>    /**<a name="line.7"></a>
<FONT color="green">008</FONT>     * &lt;p&gt;AllC Not Gate - an efficient generalized Toffoli gate.&lt;/p&gt;<a name="line.8"></a>
<FONT color="green">009</FONT>     * &lt;p&gt;The Gate flipes the target qubit if all the other qubits are 1 &lt;/p&gt;<a name="line.9"></a>
<FONT color="green">010</FONT>     * <a name="line.10"></a>
<FONT color="green">011</FONT>     * @author Richard Inskip<a name="line.11"></a>
<FONT color="green">012</FONT>     *<a name="line.12"></a>
<FONT color="green">013</FONT>     */<a name="line.13"></a>
<FONT color="green">014</FONT>    public class AllCnotMatrix extends MatrixGate {<a name="line.14"></a>
<FONT color="green">015</FONT>            <a name="line.15"></a>
<FONT color="green">016</FONT>            /** Store the target qubit the gate acts on*/   <a name="line.16"></a>
<FONT color="green">017</FONT>            private int target;<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>            /**<a name="line.19"></a>
<FONT color="green">020</FONT>             * Protected constructor to create an instance of this object<a name="line.20"></a>
<FONT color="green">021</FONT>             * <a name="line.21"></a>
<FONT color="green">022</FONT>             * @param target the target qubit to flip<a name="line.22"></a>
<FONT color="green">023</FONT>             */<a name="line.23"></a>
<FONT color="green">024</FONT>            protected AllCnotMatrix(int target){<a name="line.24"></a>
<FONT color="green">025</FONT>                    this.target=target+1;<a name="line.25"></a>
<FONT color="green">026</FONT>                    <a name="line.26"></a>
<FONT color="green">027</FONT>            }<a name="line.27"></a>
<FONT color="green">028</FONT>            <a name="line.28"></a>
<FONT color="green">029</FONT>            /** The apply method which will allow the Gate to be appied to the Register.<a name="line.29"></a>
<FONT color="green">030</FONT>             * @param r The Quantum Register<a name="line.30"></a>
<FONT color="green">031</FONT>             */<a name="line.31"></a>
<FONT color="green">032</FONT>            public void apply(Register r) {<a name="line.32"></a>
<FONT color="green">033</FONT>                    if (target &gt; r.getNumQbits() || target &lt; 1){<a name="line.33"></a>
<FONT color="green">034</FONT>                            throw new IllegalArgumentException("Target qubit not in register. Register size (qubits): " + r.getNumQbits() + " Target qubit: " + target);<a name="line.34"></a>
<FONT color="green">035</FONT>                    }<a name="line.35"></a>
<FONT color="green">036</FONT>                    int numStates = r.getNumStates();<a name="line.36"></a>
<FONT color="green">037</FONT>                    int intervalSize = (int)(numStates/Math.pow(2,target));<a name="line.37"></a>
<FONT color="green">038</FONT>                    Matrix AllCnot = Matrix.IdentityMatrix(numStates);<a name="line.38"></a>
<FONT color="green">039</FONT>                    AllCnot.setElement(numStates-1, numStates - 1,new Complex(0)); <a name="line.39"></a>
<FONT color="green">040</FONT>                    AllCnot.setElement(numStates-1-intervalSize, numStates-1-intervalSize, new Complex(0));<a name="line.40"></a>
<FONT color="green">041</FONT>                    AllCnot.setElement(numStates-1-intervalSize, numStates - 1, new Complex(1));<a name="line.41"></a>
<FONT color="green">042</FONT>                    AllCnot.setElement(numStates-1,numStates-1-intervalSize,new Complex(1));<a name="line.42"></a>
<FONT color="green">043</FONT>                    r.update(AllCnot.multiplyMatrix(r));<a name="line.43"></a>
<FONT color="green">044</FONT>            }<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>            /**<a name="line.46"></a>
<FONT color="green">047</FONT>             *  Return the name of the matrix.<a name="line.47"></a>
<FONT color="green">048</FONT>             */<a name="line.48"></a>
<FONT color="green">049</FONT>            public String getName() {<a name="line.49"></a>
<FONT color="green">050</FONT>                    return "AllCnot";<a name="line.50"></a>
<FONT color="green">051</FONT>            }<a name="line.51"></a>
<FONT color="green">052</FONT>    <a name="line.52"></a>
<FONT color="green">053</FONT>    }<a name="line.53"></a>




























































</PRE>
</BODY>
</HTML>
